Adaptive Neuro-Fuzzy Based UPQC in A Distributed Power System for Enhancement of Power Quality

Abstract

The power quality problems during distribution of power are mainly occurs due to transient distortions in the line voltage like harmonics, flicker, sags and swells. These power quality issues can cause damage of equipment, losses in power transfer or even can lead system towards instability. To alleviate these complications, ANFIS based UPQC is to be proposed. The object of this work is to develop the power quality all over and done with a new unified grid-connected inverter-based distributed power system by using ANFIS-UPQC. In this paper ANFIS based UPQC (ANFIS-UPQC) is being used as a Facts controller to mitigate together current & voltage distortions at the consumer end of Distribution system. The concert of ANFIS-UPQC has very precise dynamic response by means of a very simple design of control circuit. This paper shows validation of ANFIS based UPQC and Results are compared with UPQC by means of hysteresis control Band by means of PI controller and improvements are observed. The ANFIS-UPQC reduces the harmonics at highly accepted level compared to PI Controller based UPQC. The simulation results, carried away by MATLAB/Simulink, shows that ANFIS-UPQC has a less THD and the output voltage/Current profiles are improved compared to PID Controller based UPQC.

Introduction

It’s always a challenge to distribute the electric power without loss and it is necessary to retain the power quality within the limits. For achieving this, one of the newly developed Facts controllers is UPQC. It’s a Facts device that consists of end-to-end connected two 3-ϕ ACTIVE POWER FILTERS (APFs) i.e. series and shunt inverters with a common DC-link. The shunt inverter of UPQC acts as a CSI for injecting current from end to end of a transformer in parallel, while the series inverter acts as a VSI for feeding voltage across a transformer in series. PCC can be extremely distorted; also the changes in highly rated load linked to PCC may result into

voltage distortions on the PCC has been discussed [2]-[3]. Here, using of UPQC at PCC is an effective approach to care for the distribution system from sensitive loads. UPQC is a flexible device that can compensate nearly all power quality issues such as voltage sags/swell, voltage distortions, current distortions etc. The effect of sags can be less destructive than swells. For example, the high voltage during swell condition may cause insulation damage or breakdown in components or equipments. Due to unexpected changes of line current in the source impedance, voltage sag/swells takes place in the distributed system. The main aim is to keep the load bus voltage to be sinusoidal and the chief concern is the flow of active & reactive power in this situation. It shows a vital role to choose the KVA ratings of both APFs. Among latest technical options available to enhance power quality, UPQC has set up more promising for compensate of current/voltage harmonics at the same time. As per literature review, application of UPQC for alleviation of voltage/current harmonics has been presented. It is normally constituted with two voltage source converters connected back to back through a DC-interface capacitor.

Conclusion

This paper is for the most part dedicated to the investigation of Power Quality issues and its remuneration with Unified power quality conditioner (UPQC). Results obtained from this examination give helpful data with respect to the conduct of various controllers used for control quality change associated with grid. The controllers for the most part utilized for control quality change from PI to Adaptive neuro fuzzy controller (ANFIS). The advancement comes about validate that the UPQC with PI Controller Compensates 85% of voltage transient, While UPQC with Adaptive neuro fuzzy controller (ANFIS) Compensates 98% of voltage transient. Thus when contrasted with the reaction acquired with PI Controller, Adaptive neuro fuzzy controller (ANFIS) based controller have awesome favorable position of flexibility.